High Temperature Electronics for Geothermal EnergyWork performed under the auspices of the U.S. Department of Energy, Contract No. DEAC0476PD00789 for the Division of Geothermal Energy (DGE).

The worldwide production of electric power from geothermal energy sources at present is 1.2 GW. The largest facility is in the United States at The Geysers, in Northern California, where 605 MW is on-line. Recent estimates indicate that geothermal energy sources could produce over 10 GW of power in the USA by 1990; however, to achieve this goal there must be accelerated exploration and development. Developers and investors may be reluctant to make the necessary commitments if there is high risk or uncertainty in a geothermal reservoir's production potential. Also, once a system is in operation, engineers periodically need accurate and timely downhole information from each well in order to obtain optimum production. Instrumentation for geothermal borehole measurements is being expanded beyond today's limited capabilities. Prototypical logging tools have been successfully field-tested to 275° C; a highresolution quartz pressure transducer and a gallium phosphide diode have been successfully tested. Near-term goals of current programs are to develop instrumentation for use at 275° in pressures up to 48.3 MPa (7,000 psi).